Project 3
       PYTHON OBJECT MODEL
             OBJECT ORIENTED DESIGN
                            Object Oriented Programming                 1
     Download the file graphics.py from the link:
    https://samyzaf.com/braude/PYTHON/projects/graphics.py
     This file implements our graphical environment. Specifically, it defines a 
       canvas window on which we can draw points, lines, rectangles, and 
       other geometrical shapes
     There is no need to read or understand the code in this module
     It is based on the the Tkinter module, which is the simplest graphics 
       environment that comes with any Python distribution and is therefore 
       always available
     If you want to experiment with graphics programming, you may start 
       with: 
       http://www.tkdocs.com/tutorial/
                                    Object Oriented Programming                            2
     p = Point(x,y)                                     [constructor]
          Create a new point p from two integers: x, y
          Our domain is the two-dimensional plane for abstract circuit design (CAD system)
     p.x = x coordinate                                                  [field]
     p.y = y coordinate                                                  [field]
     p.move(dx, dy)                                     [mutator]
          Move the point p to new coordinates: x+dx, y+dy
     p.draw()                                           [accessor]
          Draw the point on the screen
     p.text(t)                                          [accessor]
          Draw a texts string t above the point
                                     Object Oriented Programming                              3
    Reminder: in test driven methodology you write your tests before the implementation of 
      your ADT !!!
    After implementation, your tests should run and PASS after each modification you make 
      to your implementation (“nightly test regression”)
    The following tests are your “insurance policy” that your implementation is correct. The 
      more tests you write, the more you’re insured
          # Testing our Point ADT: test 1
          def test1():
              print "===== Testing The Point Class ====="
              p1 = Point(20,20)
              p2 = Point(50,60)
              print "Testing the Python print statement on Point p1:"
              print p1
              print "Testing the Python print statement on Point p2:"
              print p2
              print "Test 1: PASSED"
                                Object Oriented Programming                       4